VANDENBERG AIR FORCE BASE, Calif. (AP) - An Air Force missile test Thursday provided a spectacular light show seen over California and much of the West, as far away as Utah and New Mexico.

The colorful contrail was seen soon after the unarmed Minuteman III intercontinental ballistic missile blasted off at 7:36 p.m. from an underground silo at the Vandenberg military base north of Santa Barbara.

"The smoke went up in spirals as the sun was setting and turned into an orange, amber color. It was like a flower going into bloom pretty quickly," said Simon Cox, who saw it from a restaurant terrace in Santa Barbara.

The missile traveled about 4,200 miles in about 30 minutes, striking a predetermined target at the Kwajalein Missile Range in the western chain of the Marshall Islands, the Air Force said.

"We do this two or three times a year, but because the weather was so perfect we decided to launch it early," Gabel said. As a result, people were still awake to see it, and although the sun had set, sunlight below the horizon glinted off unspent fuel particles and water droplets.

"Suddenly we're getting calls from people as far away as New Mexico who saw it and want to know what it is," Gabel said.

The mission was directed by the 576th Flight Test Squadron at Vandenberg and the 341th Space Wing and the 341st Space Wing, from Malmstrom Air Force Base in Montana.

The purpose was to test launch systems and the missile's accuracy and reliability.